'The 'greening' effect of CO2 will ultimately be overwhelmed by the plants' own respiration and decay, which will cause even more CO2 to be released.' 'What this research does not show is that humanity can relax when it comes to the dangers to agriculture posed by climate change. The authors make it clear that this effect is almost certainly temporary. 'But we don't know exactly where the carbon sink is increasing the most, how long this increase will last, or what it means for the future of Earth's climate.'īritish climate scientist Professor Chris Rapley, from University College London, said: 'This study points out that over the last decade the atmospheric CO2 content and global temperature continued to rise, but the rate of temperature rise slackened as a result, plants appear to have absorbed CO2 more readily. 'We've shown the increase in terrestrial carbon uptake is happening, and with a plausible explanation why. But CO2 take-up by vegetation should not be seen as a solution to global warming, the scientists warned.ĭr Keenan said: 'Unfortunately, this increase is nowhere near enough to stop climate change.
Thanks to the plants, the amount of human-generated carbon remaining in the atmosphere had actually fallen by 20 per cent. In comparison, human activity was emitting between nine and 10 petagrams of carbon per year. This had risen from between one and two petagrams (trillion kilograms) of carbon per year to two to four petagrams. The models suggested that rising CO2 levels caused land-based ecosystems to double their carbon uptake between the 1950s and 2000s, the researchers reported in the journal Nature Communications.Ī study suggests that global warming has led to a global greening, with plants soaking up carbon dioxide as they grow, countering the effect of increasing amounts of carbon in the atmosphere
Besides vegetation, other carbon sinks include the oceans and peaty soil.Ĭomputer simulations combined with satellite observations of vegetation and ground and atmospheric measurements of CO2 pointed strongly to plants. The scientists suspected the carbon must be disappearing into a 'sink'.
The 'pause' in CO2 build-up was surprising because it had occurred at a time when human activity was pumping record amounts of carbon into the atmosphere. Study author Dr Trevor Keenan, from the US Department of Energy's Berkeley National Laboratory, said: 'This highlights the need to identify and protect ecosystems where the carbon sink is growing rapidly.'ĭuring the latter half of the 20th century, the growth rate of atmospheric CO2 climbed steadily from 0.75 ppm/year in 1959 to 1.86 ppm/year in 2002.īut an analysis of the latest data last year by Dr Keenan's team found that since 2002, the growth rate had remained flat.
0 kommentar(er)
